How Honey Bees Keep Warm in Winter

Thermoregulation in Winter Honey Bee Hives

Honey bee hives in the snow.
How do honey bees survive the winter?.

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Most bees and wasps hibernate during the colder months. In many species, only the queen survives the winter, emerging in spring to reestablish a colony. But honey bees (species Apis mellifera) remain active all winter long, despite the freezing temperatures and lack of flowers on which to forage. Winter is when they reap the benefits of their hard work, by living off the honey they've made and stored.

Winter Is Why Bees Make Honey 

The honey bee colony's ability to survive the winter depends on their food stores, in the form of honey, bee bread, and royal jelly. Honey is made from collected nectar; bee bread is combined nectar and pollen which can be stored in cells; and royal jelly is a refined combination of honey and bee bread eaten by nurse honey bees. The bees keep warm by consuming honey and bee bread. If the colony runs short of honey, it will freeze to death before spring. The worker bees force the now useless drone bees from the hive, letting them starve. It's a harsh sentence, but one that's necessary for the colony's survival. Drones would eat too much of the precious honey, and put the hive in peril.

Once sources of forage disappear, the remaining honey bees settle in for the winter. As temperatures fall below 57° F, the workers hunker down near their cache of honey and bee bread. The queen stops laying eggs in late fall and early winter, since food stores are limited and the workers must focus on insulating the colony.

The Honey Bee Huddle

The honey bee workers huddle, heads pointed inward, into a cluster around the queen and her brood to keep them warm. Bees on the inside of the cluster can feed on the stored honey. The outer layer of workers insulates their sisters inside the sphere of honey bees. As ambient temperatures rise, the bees on the outside of the group separate a bit, to allow more air flow. As temperatures fall, the cluster tightens, and the outer workers pull together.

As the ambient temperature drops, the worker bees actively generate heat within the hive. First, they feed on honey for energy. Then, the honey bees shiver, vibrating their flight muscles but keeping their wings still, which raises their body temperatures. With thousands of bees constantly shivering, the temperature at the center of the cluster warms up to about 93° F. When the workers on the outer edge of the cluster get cold, they push to the center of the group, and other bees take a turn shielding the group from the winter weather.

During warmer spells, the entire sphere of bees will move within the hive, positioning themselves around fresh honey stores. During long spells of extreme cold, the bees may be unable to move within the hive. If they run out of honey within the cluster, the bees can starve to death just inches from additional honey reserves.

What Happens to the Bees When We Take Their Honey?

An average colony of honey bees can produce 25 lbs. of honey during the foraging season. That's two to three times more honey than they typically need to survive the winter. During a good foraging season, a healthy colony of honey bees can produce as much as 60 lbs. of honey. So the industrious worker bees make much more honey than the colony requires to survive the winter.

Beekeepers can and do harvest the surplus honey, but they always make sure they leave a sufficient supply for the bees to sustain themselves through the winter months. 

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